Photoresist composition, a method for manufacturing a photoresist coating, etched photoresist coating, and etched Si containing layer(s), and manufacturing a device using thereof

A photoresist composition comprising

• (A) a single or a plurality of polymer whose solubility changes under the existence of acid,
• (B) a single or a plurality of photo acid generator,
• (C) a single or a plurality of compound comprising unit EO and unit PO, and
• (D) a single or plurality of solvent,
• wherein the unit EO is represented by following formula (1),
• and the unit PO is represented by following formula (2)
• wherein the weight average molecular weight (Mw) of the (C) compound(s) is 1,000-50 000,
• the mass ratio of the (C) compound to the (A) polymer is 3-50 mass %, and
• the terminals of the (C) compound are modified by R1— and R2—O—,
• where R1 is C1-10 alkyl, and R2 is hydrogen or C1-10 alkyl.